Critics of Vedanta and many layman and even Hindus say that Vedanta is foolish as it teaches world is not real. They say that Vedanta emphasizes the unreality of the world, saying, jagat mithya: the world is not real. Such people criticize: ‘It is foolish to say that my spouse, children, home, car, money, and other things are not real.’
The definition of Vedanta is ‘Satyatvam hai-asman-mate trikala-abadhyatvam;’ (Truth is that which exists always). According to our opinion the real is indeed that which does not cease to exist in the past, present, and future. But is there any such thing in this world? All that you hold real and ear do you think they will be permanently be with you?
According to Vedanta, there are two kinds of reality: the absolute and the relative. Brahman (God in general sense) is the absolute Reality, while the world is the relative reality. Yes, your spouse, children, headache, and stomach-ache are relatively real. They come and go.
From the absolute standpoint, the world is not real. Nonetheless, an unreal doctor can remove an unreal disease by providing unreal medicine to an unreal patient. Similarly, an unreal guru can use an unreal mantra to remove the unreal ignorance of an unreal disciple.
Asat refers to something that does not exist and that cannot be seen such as a bandhya putra, a son of a barren woman. Mithya refers to something that does not exist but can be seen, such as water in a mirage. When the sun reflects on sand in a desert, we see something that looks like water. This is as illusory as the world itself.
When you are in deep sleep, where do your spouse, children, and other things go? They disappear from the mind. When you wake up in the morning, the world reappears in the mind. So, Vedanta says that this universe is ‘manasah-spandanamatram; just the vibration of the mind’. Our bodies are our worlds. We understand very well that the body is not permanent. This world is a vacation village.
Source - Excerpts from ' What Vedanta Means to Me by Swami Chetanananda' - Prabuddha Bharata January 2020 issue.